Exceptions instead of return codes, exit

yccp/sweeps/parametersets.py

@@ -8,6 +8,7 @@
 from .. import prelude as pl
 
 import copy
+import errno
 import os
 import os.path as osp
 
@@ -93,7 +94,7 @@ def setup_metadata(self, orig_file):
                 "transforms": [],
             }
 
-    def write(self, filename, overwrite=False, failOnOverwrite=True):
+    def write(self, filename, overwrite=False):
         """
             Dump data into filename.
         """
@@ -109,11 +110,7 @@ def write(self, filename, overwrite=False, failOnOverwrite=True):
             log.error(
                 "File {} exists and overwrite was not set to True".format(
                     filename))
-            if failOnOverwrite:
-                exit()
-            else:
-                return 1
+            raise OSError(errno.EEXIST)
         else:
             with open(filename, "w") as f:
                 pl.dump(self.data, stream=f)
-                return 0

yccp/sweeps/sweeps.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python2
 # encoding: utf-8
 
+import errno
 import inspect
 import itertools as it
 import logging
@@ -87,10 +88,14 @@ def dump(self,
 
             if write_files:
                 log.info("Writing: {}".format(fn))
-                if 0 == ps.write(fn, overwrite=overwrite_files, failOnOverwrite=failOnOverwrite):
+                try:
+                    ps.write(fn, overwrite=overwrite_files)
                     written_filenames.add(fn)
-                else:
-                    overwritten_files.add(fn)
+                except OSError as e:
+                    if e.errno == errno.EEXIST and not failOnOverwrite:
+                        overwritten_files.add(fn)
+                    else:
+                        raise
             else:
                 log.info("Would write: {}".format(fn))
                 written_filenames.add(fn)

yccp/utils.py

@@ -26,9 +26,8 @@ def get_recursive(dct, path, default=None, sep="/"):
     retval = retrieve_path(dct, path, sep, create=False)
     if retval is None:
         if default is None:
-            import sys
-            sys.exit("YCCP: Did not find {} in the given document. "
-                     "Skip this by giving sensible (not None) default".format(path))
+            raise KeyError("YCCP: Did not find {} in the given document. "
+                           "Skip this by giving sensible (not None) default".format(path))
         retval = default
     return retval